pgsql: Handle AT_ReAddComment in test_ddl_deparse, and add a catch-all

Handle AT_ReAddComment in test_ddl_deparse, and add a catch-all default.

In the passing, also move AT_ReAddComment to more logical position in the
enum, after all the Constraint-related subcommands.

This fixes a compiler warning, added by commit e42375fc. Backpatch to 9.5,
like that patch.

Branch
------
REL9_5_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/e66e31958fc5f5346394099a6481a7949cc1f02a

Modified Files
--------------
src/include/nodes/parsenodes.h                       |    2 +-
src/test/modules/test_ddl_deparse/test_ddl_deparse.c |    5 +++++
2 files changed, 6 insertions(+), 1 deletion(-)